You can use whatever CAD software you want so long as it supports saving as a .DXF file. I used Graphite and it worked splendidly. It was my first time using it and I had my doubts at first, but I love it now :)
The dragonfly sketch is saved below. Feel free to do whatever you want with it!
You will notice that the entire dragonfly is at the top of the image and then halfway down it mirrors (kinda) so that the dragonfly can fold the belly underneath the top half so as to have a real 3D model.
Two corrections (possibly 3):
the legs don't quite work as drawn (the are directly flush with the wings and two short to reach the ground)
the bottom of the head doesn't quite line up with the body. I would make the body side flaps thinner to avoid this.
the tail is too long. I knew this going into the drawing since I was confined to a certain amount of space.
If you have any questions, post them either by messaging or in the comments below.